Control mechanism



| R. SMITH ET AL 2,127,539

CONTROL MECHANISM Original F'il ed Feb. 14, 1954 ii? F1043.

WITNESSES: INVENTORS L'R-SMITH and u) I W'A-MINKLE'B.

: I BY r f Patented Au 23, 193

j PATENT OFFICE con'rnor. MECHANISM Lewis a. Smith and William A. Minkler, Pittsburgh, Pa., assignors tric & Manufacturing to Westinghouse Elec-g' Company, East Pitts burgh, Pa., a corporation of Pennsylvania Application February 14, 1934, Serial No. 711,106 Renewed July '1, 1937.

12 Claims (01. 62- -129) Our invention relates to a control system'for air cooling apparatus and it has for an object to provide an improved system therefor.

It is a further object of our invention to provide an improved control system for a plurality of air cooling devices which are supplied with a cooling medium from a common source of limited capacity. A still further object of this invention is to pro- 10 vide a control system, for a plurality of air cooling devices receiving refrigerant from 'a common source, which limits the refrigerating load applied to said source to the capacity thereof. While not necessarily limited thereto, our in- 15 vention. is more applicable to relatively small air 1 cooling devices, such as are used for cooling air in the home and small storerooms; and which are commonly referred to as roomcoolers. These devicesusually include a cabinet structure, within 20 which a cooling coil or evaporator is disposed and a fan for circulating air in heat exchanging relation with the cooling coil and delivering it to the room in a cooled condition. The cooling coil or evaporator is supplied with refrigerant from a 25 refrigerating machine which may be of any well known type. 1

It is often desired to operate two or more cooling devices from a single refrigerant source, the

capacity of which is limited to the requirements 30 of a single device. For example, an air cooling device ,may be installed in the lower floor of a home and one on the upper or bedroom floor.

During the day, the cooler on the lower floor is operated, and, in the evening, the upper floor cooler on the lower floor terminated. An eflicient system isprovided by an arrangement of this kind where a refrigerating machine having a capacity capable of operating one device at a time 40 constitutes the refrigerant source. The machine while in operation is running under optimum conditions at full load. It is to arrangements'of this kind that our novel control system applies.

In practicing our invention, we provide a se- 45' lector switch, movable to a plurality'of selective positions, each position of'which renders a different air cooling device operable. operable device may be further controlled by a manually-operated disconnecting switch adjacent to to the cooler, cabinet and/or a temperature responsive instrument disposed within the space being cooled.

The fan associated with each device is preferably so connected to the:,electrical source that it maybe operated independently of any of the The selected switches mentioned in the foregoing in order that it may be operated at any time. for ventilation. However, operation .of the fan is desirable at all times that its associated cooling device is operative and provision is made in our novel system to assure this operation.

These and other objects are effected by our invention, as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a diagrammatic view of air cooling apparatus having our novel control system applied thereto;

Fig. 2 is a diagrammatic view of a modification of the selector switch employed; and,

Fig. 3 is a straight line wiring diagram of the control system shown in Figure l.

Reference will now be had to Fig. 1 in which we have disclosed a plurality of air cooling devices III, I I, and II, respectively, disposed within spaces or enclosures A, B, and C, to be air-conditioned. As the air cooling devices are of similar construction, we have shown but one-of them in section and a description of but one will be given; it being understood that all have corresponding elements. Each of the devices includes a cabinet l3 having an inlet opening l4 and an outlet opening IS in communication with the enclosure inwhioh it is located.- A cooling coil'or evaporator I6, is disposed within -the cabinet I; intermediate between said inlet and outlet 'openings. A motor driven fan I1 is arranged adjacent the inlet opening ll for drawing in air therethrough and for translatcooler is placed in operation and operation of the n t through t e cabinet l3 an t e O t Ope 35 ing l5 to the enclosure. Suitable provision for fresh air may be made. I

The evaporators 16 receive refrigerant from a common refrigerating machine It, preferably'oi' the compressor-expander type. The latter ma- 40 chine includes a compressor, driven by a motor 20, for withdrawing vaporized or spent refrigerant from the evaporator l6 and for compressing it, and a condenser 2| for condensing the same. The refrigerating machine l8. has a capacity suflicient to meet the requirement of any one of the air cooling devices 10" II, and llwhen operated singly, but insuflicient for multiple operation.

The system operates on the well known compression-expansion cycle in which refrigerant vapor is withdrawn from one of the evaporators I 6, depending upon which is selected for operation, through a branched conduit 22, compressed by the compressor I9 and conveyed to the condenser ii. The compressor vapor is cooled and liquefied in 23. Liquid refrigerant from the reservoir 23 is conveyed by a branched conduit 24 to an expansion device 25, through which it is admitted under reduced pressure to the evaporator I6. Due to the low pressure produced by the suction of the compressor I9, refrigerant is vaporized in the 1 evaporator I6, absorbing heat therefrom in a Well I which will be described hereinafter.

As the capacity of the refrigerating machine I8 is a fraction of the total refrigeration requirements of the air cooling devices, we have provided a novel control system to limit the number of devices which may be connected to the refrigerating machine at any one time to a number whose total refrigeration requirements do not exceed the capacity of the refrigerating machine I8. In the present case, the refrigerating machine I8 is assumed to have sumcient capacity to supply refrigerant to only one of the cooling devices I0, II, and |2, so that the control system permits refrigerant to be supplied to only one of said cooling devices at a time.

The air cooling device I6 has a two-pole switch 33 and a single pole switch 34 associated therewith, which switches, are disposed adjacent to the device and are preferably carried by the cabinet thereof. Similarly, the device II has switches 35 and 36 associated therewith and the device I2 includes switches 31 and 39. The control system also includes selector switches 39 and 4| which are preferably located centrally with respect to the devices Ill, II, and I 2' where they may be conveniently reached from any one of the three. It will be obvious that the location of these switches will vary with different installations. The selector switch 39 includes a movable contactarm 42 and stationary contacts 43,

44, and 45 and the switch has a movable con-' tact arm 46 and stationary contacts 47, 48, and 49. The electrically operated valves 29, 3| and 32 are of well known construction, and are perfer ably opened and closed by the energization and deenergization of solenoids associated therewith. The solenoids for operating the valves 29, 3| and 32 are shown at 53, 62, and 65, respectively, and are so arranged that, when energized, their respective valves are opened, and, when deenergized, their valves are closed. As these valves are well known in the art, no further description of them is deemed necessary.

. The motor 20 for driving the compressor I9 may be connected directly to the power source when the proper switches, mentioned in the foregoing description, are adjusted to their closed positions, but we prefer to effect this connection by means of a relay shown at 56. This'relay includes switches 51 connected in the circuit of the motor 20 and a solenoid .55 which, when energized, closes the switches 51 and, when deenergized, opens the same.

Automatic control of the air cooling device III,

I I, or I2 in accordance with a condition of the air in the spaces served thereby may be effected if desired. We have shown thermostats 6| for automatically controlling the devices II and I2 in accordance with the temperature in the spaces B and C, respectively. The thermostats 6| are electrically connected in the circuits of the devices II and I2; the specific connections being described hereinafter. As the electrical connections between the various elements are clearly 2,127,539 the condenser 2| and may be stored in a reservoir shown in the drawing, no detailed description of them will be necessary, and the reference to them in the mode of operation which follows, clearly outlines their function.

Operation Assuming it is desired to cool the air in the enclosure A, the switch 33 will be closed and, the

arms 42 and 46 of the selector switches moved into engagement with the contacts 43 and 41,

respectively. A circuit is thereby closed which extends through the coil 53 of the refrigerant valve 29. This circuit may be traced from a line conductor 5|, arm 46, contact 41, switch 33, con-" ductor 54, coil 53 to the other line conductor 52. A parallel circuit is also formed from the energized conductor 54 to the coil 55 of the relay 56, which controls the energization of the compressor'motor 20. This circuit may be traced from conductor 54, contact 43, arm 42, coil 55 to the line conductor 52. Refrigerant is now permitted to flow to the evaporator |6 from the supply pipe 24 as the energization of the coil 53 has opened the valve 29. Operation of the refrigerating machine I8 is initiated as the motor 261s electrically connected to the line conductors 5| and 52 by the closing of the contacts 51 of the relay 56. The fan I I operates due to the closing of the switch 33, the circuit through the fan motor extending from conductor 5|, the second pole of the switch 33, conductor 58, the motor of fan I I to the line conductor 52. vAir from the enclosure A is withdrawn by the fan I'l, conveyed in heat exchanging relation with the evaporator I6 where its temperature is reduced,

'and discharged upwardly into the enclosure A.

Operation of the air cooling devices I' and I2 is initiated in the same manner as previously de-' scribed in connection with the device I0, the

selector switches 39 and 4|.being moved to their' proper positions. For example, if the air cooling device I2 is to be operated, the arms 42 and 46 of the selector switches are moved into engagement with contacts 45 and 49, and the switch 31 is closed. When the arms 42 and 46 are moved to the off position shown on the drawing, the

circuits of the several coils 53, 62, 65 and 55 are switch 35 is-closed, the arm 42 engaged with' contact, and the arm 46 engaged with contact 48. The contacts of the thermostats 6| are shown open, which indicates. that the temperature of the enclosure B is at the desired degree. Accordingly, the coil 62 of the refrigerant valve 3| and the coil 55 of the relay 56 are deenergized. The refrigerant machine I3 is therefore inactive, due to the open position of the switch 51, and

how of refrigerant from the supply pipe 24 to the evaporator I6 of the air cooling device II is prevented by the closed valve 3|. When the temperature of the air in the enclosure B rises above a predetermined degree, the contacts of the ther- 1 mostat 6| close to complete the circuit from the line conductor 5| arm 46 of the selector switch 4|, contact 48, switch 35, conductor 54, thermostat 6I, the coil 62 of the valve 3| to the other pleted from the energized-thermostat, con-Z tact 44, arm 42, relay coil 55 to the line conductor 52. Opening of .the valve 62 permits refrigerant to flow to the evaporator l6 of the air cooling device H and the energization of the coil 55 closes the relay contacts 51 to initiate operation of the refrigerating machine. It will be seen from the foregoing that, when an air cooling device is rendered operable by the closing of its associated control switch 33, 35, or 31, operation of the particular device is as long as closed. Where thermostatic control is employed, such as'shown in connection with the air cooling device Ii, the circuit is such that only the refrigerant valve and the refrigerating machine are initiated" and iscontinuous under control of the thermostat; operation: of r the fan l1 being independent thereof. Therefore, when any of the air cooling devices are rendered operable, uninterrupted operation of the fan associated therewith results. The fan is further controlled by switches 34, 36, or 38 which are connected in parallel with the second pole of switches 33, 35, and 31, respectively, so that the fan may be operated for ventilation even if cooling is not desired.

We have shown the selector switches 39 and II as separate devices in Fig. 1 as they are of standard construction and of a typ generally used by the electrical trade.- However, a selector switch similar to that shown in Fig. 2 may be used in which the arms 42 and are mechanically tied together so-th'at both arms are set with one operation. One form of accomplishing this is shown as comprising an insulated bar 64 mechanically connected to the arms 42 and 46. a

With the above control mechanism, it is possible, if desired, to initiate and control operation of the various room coolers from the selector switches. To do this, the switches 33, 35, and 31 are closed, which, in the present embodiment,

effects continuous operation of the aircirculat- 'ing-fans.

Then bymoving'the arms 42 and 6 to the contacts of the selected room cooler, operation thereof is eiiected,-subject,-,to the action of the thermostat if the room cooler is provided therewith. To discontinue operation of all room coolers,,the arms 42 and 46- are moved to the of! position shown in Fig. 1.

From the above description, it will be seen that we have provided 'a control system whereby the number of cooling devices in operation at one time is limited to the capacity of the refrigerant supply means. It will also be noted that the control system cannot effect operation of the refrigerating machine l8 without being connected to one of the cooling devices, since the coil 55, i

to be energized through one of the contacts of the switch 42, is necessarily connected in parallel with one of the coils controlling the refrigerant various changes and modifications, withoutfde valves.

.While we have shown'our invention in but one Y it will be obvious to, those skilled in the it is not so limited, but is susceptible of form, art that parting from the spirit thereof, and we desire,

therefore, that only such limitations shall be placed thereupon as are imposed by the prior'art or as are specifically set forth in the appended claims. i l

' What we claim is: 1. In a control system for air conditioning apparatus, the combination of a plurality of air mon to said devices, for

a My its'energized coil 'of selective positions, refrigerating machine and one, of said valves are fan I1 associated with that its'respective switch 33, 35, or 31 iscooling devices, a refrigerating machine, comproviding a supply of refrigerant therefor, a plurality of electrically operated valves for controlling the supply of refrigerant to said devices, and a selector switch for controlling the operation of the refrigerating machine and said valves and movable to a plurality in each of which the rendered operable, and to an oil position in which paratusthe combination ofja plurality of air cooling devices, a refrigerating machine, the

' the refrigerating machine and all of said valves 1 capacity of which-is a fraction of the total refrigeration requirements of the air cooling devices, for providing a supply of refrigerant therefor, a pluralityv of conduits for conveying refrigerant from the refrigerating machineto the air cooling devices, a plurality of electrically operated'valves connected in said' conduits, respec-, tively, and a selector switch for controlling the operation of the refrigerating machine and said valves and movable to a plurality of selective positions, in each of which said refrigerating machine is rendered operable and flow of refrigerant through one of said conduits may be effected, and to an off'position in which the refrigerating machine is rendered. inoperable and all of said valves are closed.

3. In' a control system for air conditioning apparatus, the combination of a plurality of air cooling .devices,'a refrigerating machine, common to said devices, for providing a supply of refrigerant therefor, electrically operated valves for controllingthe supply of refrigerant to said devices, respectively, an electrical circuit for each valve, a disconnecting switch in each of the last named circuits, and a selector switch, movable to a plurality of selective positions, for energizing both said refrigerating machine and one of said valve circuits through the respective disconnecting switch.

4. In a control system for air conditioning apparatus, the'combination of a plurality of devices for cooling the .air in a plurality of spaces, a 'refrlgerating machine, common to said devices, for I producing a supply of refrigerant therefor, electrically operated valves for controlling the supply of refrigerant to said devices, respectively, electrical circuits for said valves, switches operated in response to the temperature of the air in their associated spaces for controlling the e'ner Y gization of said circuitsfrespectively, and switching means movable to a plurality of selective positions for-energizing both said refrigerating machine and one ,of said valve circuits through the respective temperature responsive switch.

. 5.- In a control system for air conditioning apparatus, the combination of a plurality of ,cool-' ing devices, a fan associated with each device for translating air therethrough, a refrigerating machine comfhon to said devices for providing a supply of refrigerant therefor, electrically operated valves for controlling the supply of refrigerant to said devices, respectively, an electrical circuit 'for each valve, a disconnecting switch in each of the last-named circuits, a selector switch, movable to a plurality of selective positions, for energizing both the refrigeratingmachine and one of said valve circuits throughthe respective disconnecting switch, and switching means asso-' f ciated with each disconnecting switchv for controlling the operation of the fan independently of the selector switch.

6. In a control system for air conditioning apparatus,.the-combination of a plurality of air cooling devices, a refrigerating machine, common to said devices, for providing a. supply of refrigerant therefor, electrically operated valves one of said circuits, an electrical circuit for effecting operation of said refrigerating machine, and a second selector switch for connecting said last-mentioned circuit to the selectedfvalve circuit to be energized thereby.

7. In a control systemfor air conditioning apparatus, the combination, of a plurality of air cooling devices, each having a fan for translating air therethrough, a refrigerating machine, common to said devices, for providing a supply of refrigerant therefor, electrically operated valves for controlling the supply of refrigerant to said devices, respectively, an electrical circuit for each valve, a disconnecting switch in each circuit, a selector switch movable to a plurality -of selective positions for energizing one of said valve circuits through its respective disconnecting switch, a second selector switch electrically connected to the first-mentioned selector switch and to said refrigerating machine for energizing the latter when moved to a position correspond ing to the selected position of the first-mentioned selector switch and switching means associated with each disconnect switch and opened and closed therewith for controlling the operation of the fans.

8. In a control system for air conditioning apparatus, the combination of a plurality of air cooling devices for a plurality of spaces to be cooled, each device having a fan associated therewith for conveying air in heat exchanging relation with the air cooling device and to the associated space, a refrigerating machine for provid- 'ing a supply of refrigerant for the air cooling devices and common thereto, electrically operated valves for controlling the supply of refrigerant to each air cooling device, electrical circuits for each valve, a disconnecting switch in each valve circuit, an automatic switch connected in series relation with each disconnecting switch and operated in response to the temperature of the space associated therewith, a selector switch movable to a plurality of selective positions for energizing one of said valve circuits, a second selector switch connected to the first-mentioned selector switch through the disconnecting and automatic switches and, to the refrigerating machine for energizing the latter when moved to a position corresponding to the selected position of the first selector switch, and switching means associated with each disconnecting switch and opened and closed, therewith for controlling the operation of the fans independently of the temperature responsive switches and of the selector switches.

9. In air conditioning apparatus, the combination of a plurality of air coolers, electrical circuits for the respective air coolers for efiecting operation thereof, a separate switch in each of said circuits adjacent the associated air cooler, a second switch connected in each of said circuits and operable in response to the temperature of the air in the space served by the associated air cooler,-and other switch means for selectively connecting any one of said circuits to a source of electrical energy and for limiting the number of circuits that may be so connected at one time. 10. In a control system for air conditioning apparatus, the combination of a plurality of air cooling devices, a refrigerating machine for providing a supply of refrigerant for said devices, an

electrically operated valve and an electrical circuit therefor associated with each air cooling device for controlling the supply of refrigerant thereto, a separate switch associated with each circuit for controlling the associated air cooling device individually and for simultaneously controlling the refrigerating machine, and'switch means for selectively connecting any one of said circuits to a source of electrical energy and for limiting the number of' circuits that may be so connected at one time.

11. In air cooling apparatus,-the combination of a plurality of air cooling devices, refrigerating apparatus for. supplying refrigerant for said air cooling devices, a selector switch having a plurality of selective positions corresponding to various air cooling devices and an off position, and means responsive to the adjustment of the selector switch to a selected position for supplying cooling medium to the air cooling device corresponding to said selected position and for effecting operation of saidrefrigerating apparatus and responsive to the adjustment of the selector switch to the oil position for terminating supply of cooling medium 'to all the air cooling devices.

and for terminating operation of said refrigerating apparatus.

12. In a control system for air conditioning apparatus, the combination of a plurality of air cooling devices, a refrigerating machine, common to said devices, for providing a supply of refrigerant therefor, electrically operated valves for controlling the supply of refrigerant to said devices, respectively, an electrical circuit for each valve, a selector switch for selectively rendering one of said circuits operable and for rendering one or more other circuits inoperable, separate switch means connected in the'respective circuits, each switch means controlling its associated circuit when the latter is rendered operable by the selector switch, and means for effecting operation of the refrigerating machine under control of the switch means whose circuit is rendered operable by the selector switch. 

